Патент USA US2403929код для вставки
July 16, 1946. 2,403,929 cgs, KUHN, JR CATALYTIC REFORMING PROCESS Filed Aug. 22, 194g 2 sneaks-sheet 1 . By ` INI/¿-N TOR â. WJ ATTORNEY 2,403,929 Patented July 16, 1946 UNITED STATES PATENT GFFICE 2,403,929 C_ATALYTIC REFORMîNG PROCESS Carl S. Kuhn, Jr., Dallas, Tex., assìgnor to Socony Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York Application August 22, 1942, Serial No. 455,775 2 Claims. l This invention relates to the catalytic rear rangement or reforming of branched-chain hy drocarbons and is especially concerned with the manufacture of complete aviation gasolines using relatively narrow-boiling fractions of such hydro (Cl. 260--683.4) >`arrangement to yield a mixture of branched chain hydrocarbons which boils over a relatively wide range, Another object is to afford a process for treating a relatively narrow-boiling fraction carbons. It is well known that in order to insure proper carburetion and combustion of motor fuel, the of alkylate gasoline or similar gasoline, consist ing essentially of branched-chain hydrocarbons in order to yield a complete aviation gasoline of not substantially less octane value. Still another so as to promote a molecular conversion or rear .5,5 liquid phase and therefore sufficient pressure is object is to provide a process for synthesizing a distribution of hydrocarbons in the gasoline boil ing range should be uniform, A preponderance 10 complete aviation gasoline from gaseous hydro carbons. These and other objects will be appar of either light or heavy material leads to uneven ent from the following description of my inven `carburetion‘and uneven burning, This is recog tion. nized by users, and this recognition is reflected in My invention is based upon the discovery that purchasing specifications which require reason if a relatively narrow-boiling fraction of gasoline able distribution of material across the entire boiling, branched-chain hydrocarbons is treated boiling range of the fuel. Such requirement is in the presence of an alkylation catalyst under usually arrived at by specifying that the product alkylating conditions of temperature and pressure be such that only given percents of it shall dis- f for a, controlled period of time, a gasoline frac till over at each of several given `temperatures in 20 tion having desired distillation characteristics the boiling range. may be produced therefrom. If desired, the During recent years production of high octane narrow-boiling fraction may be reformed to pro value gasolines by synthesis from lighter hydro duce a complete aviation gasoline having the carbons has assumed increasing importance an-d proper distillation characteristics. Moreover, the widespread usage. Thus, for example, in proc esses known to the art, high octane gasolines 25 gasoline-boiling product formed by my process possesses substantially as high an octane rating may be prepared by alkylating normally gaseous as that of the original narrow-boiling, branched isoparaiiins with normally gaseous oleñns in the chain hydrocarbon fraction. presence of such catalysts as sulfuric acid, phos In general, the conditions under which the phoric acid, aluminum chloride, etc. Likewise, in alkylation catalysts reform alkylate or other my copending application S. N, 320,097, ñled Feb narrow-boiling hydrocarbons are essentially the ruary 2l, 1940, there is disclosed a similar alkylat same as those under which they will produce ing process using hydrogen fluoride as a catalyst. alkylate from lighter paraiiins and olefins, ex Branched-chain hydrocarbons of high octane cept that sufñcient additional reaction time must value are prepared also by polymerization of gase be provided to obtain a reformed product of the ous oleñns, and the polymers are usually hydro desired characteristics, Thus, for example, when -genated to give a saturated product. a catalyst consisting essentially of hydrogen fluo Since alkylation processes, as usually con ride is used, the hydrogen fluoride should be of ducted, eiîect predominantly the condensation of at least about 90% concentration, and a tempera one particular isoparafñn with one particular ture preferably between about -lO and about olefin, the resulting alkylate gasoline, although of +30° C. should be employed. It is to be under high octane value, is composed essentially of stood, however, that since hydrofluoric acid, un branched-chain isomers of one parafflnic hydro like sulfurie acid, is not an oxidizing acid, rather carbon. Therefore, the alkylate is of relatively high temperatures up to about 200° C. may be narrow-boiling range, or, at least, it does not have a. required uniform distribution of hydrocarbons 45 used if desired. Since it is generally preferable to operate with the hydrocarbons in the liquid across the desired gasoline-boiling range. This phase, the critical temperature of the hydrocar is one of the reasons why alkylate gasoline is now bon being reformed will frequently set the upper conventionally blended with gasoline of inferior temperature limit for liquid phase operation. anti-knock value in order to form blended gaso line of proper distillation characteristics and va 50 The alkylating conditions for such catalysts as sulfuric acid, aluminum chloride, etc., are well por pressure. known. Accordingly, it is an object of this invention to As stated previously, the reforming reaction is provide a process for treating a relatively narrow preferably carried out with the reactants in the boiling fraction of branched-chain hydrocarbons eficaces 3 used to maintain the reactants in this liquid phase. Suitable agitating means should be pro vided in order to afford efficient contacting of the hydrocarbons and the catalyst as is custom ary in the alkylation art. Liquid phase opera tion is not essential, however, and lower pressures may be used if desired. The relative proportions of the catalyst to the 4 . the heptanes formed by the alkylation of iso butane with propylene. It is my belief, although my invention should not be limited to any par ticular theoretical considerations that under a given set of reaction conditions, the reaction time is primarily dependent upon the configura tion of the carbon atoms in the charge stock4 This discussion of reaction time is directed to batch operation. Continuous processing, of alkylation processes. Within certain limits, in 10 course, permits the use of much shorter con creasing the amount of catalyst increases the tact times as is well understood in the art. It is difîìcult to state definitely which catalyst amount of reforming obtained in a given time. total hydrocarbons are similar to those used in In the case of solid or immiscible liquid catalysts, and to a certain extent with a soluble catalyst, increased agitation increases the amount of re forming obtained in a deñnite time period since the agitation produces better contact between the catalyst and hydrocarbons. Alkylation reactions are generally carried out or catalysts will effect the desired amount of reforming in the shortest period of time, since this also varies with charge stockA and the re action conditions. I have found, however, that with certain alkylates one catalyst is preferable, while with other alkylates another catalyst will be preferred. For example, the heptanes formed in the presence of a large excess of isoparañìns. 20 Iby the alkylation of isopentane with ethylene In this respect, as well as in the reaction time, the reforming reaction is different. The amount will be reformed most effectively with alumi num chloride, While the heptanes formed by the ' of excess isoparaiiin over that required to com alkylation of isobutane with propylene will be reformed by hydrogen fluoride substantially as bine with the oleñn is generally of the order of upwards of 460 mol percent in the case of alkyl 25 rapidly as with aluminum chloride. For the most part it may be stated that those alkylation ation reactions. In contrast thereto, reforming catalysts which are most effective for the forma reactions will proceed most rapidly in the ab sence of additional isoparaihnic hydrocarbons, tion of a particular alkylate are most effective although limited amounts of light isoparafiins or for its catalytic rearrangement. Aluminum chloride and hydrofluoric acid have high-boiling, saturated hydrocarbons up to not 30 been mentioned above as typical catalysts suit over` 100 to 200 mol percent of the hydrocarbon able fcr my reforming process. It is to be un being reformed, may be present as will be dis derstood that any hydrocarbon alkylation cat cussed more in detail later in the description of alyst is likewise suitable. The various catalysts my invention. rI‘he exact reaction time for each individual 35 must, of course, be used under conditions of tem reforming operation» must be worked out by a perature, pressure, concentration, etc., at which consideration of several factors. Thus the re forming time factor is dependent upon the par ticular alkylate or other isoparañinic hydrocar they are effective as alkylation catalysts. rThe following are illustrative of alkylation catalysts which are particularly useful in my process: hy bon stock being reformed, the catalyst, the ratio 40 drogen fluoride, sulfuric acid, aluminum chlo of catalyst to hydrocarbons, the efficiency of con ride, aluminum bromide, and boron trifluoride. tact between catalyst and hydrocarbons, the tem My invention is not, however, to be construed as limited to the use of the aforementioned cata perature, the speciñcation characteristics de sired in the reformed product, etc. Although the 45 lysts. In general, aluminum chloride represents the preferred catalyst for use with the less reaction may be speeded up by increasing the highly branched-chain paranins, whereas hy temperature, increase in the temperature will in drogen fluoride represents the preferred catalyst some cases produce an increase in the amount for use with the more highly branched-chain of side reactions such as polymerization of any Aluminum . .bromide corresponds oleñns formed as intermediate products in the 50 paraflins. reforming reaction. Accordingly, even with rather closely to aluminum chloride, While sul non-oxidizing catalysts, the temperature is gen furic acid more nearly resembles hydrogen fluo ride in its catalytic reforming properties. erally kept below about 80 to 90° C. kIn general I am aware that some of the alkylation cata the reaction time used in carrying out the de sired amount of rearrangement will vary 'be 55 lysts will isomerize normal paraiîinic hydrocar bons to produce branched-chain parafûnic hydro tween about 1 and 24 hours. For a given set carbons. For example, Nenitzescu and Dragen of conditions of temperature, catalyst concentra have disclosed that aluminum chloride will iso tion, etc., one of the most important factors in merize normal hexane and normal heptane to determining the amount of time required for a particular reforming operation is the particular 60 produce branched-chain hexanes and heptanes (of. Berichte, 66 B, 1892 (1933)). The iso charge stock being subjected to the process. merization of normal parafûns to corresponding The charge stocks of primary concern for re branched-chain hydrocarbons by aluminum bro forming are the various octane and heptane al mide has been demonstrated by Glazebrook, Phil kylates, and the range of reaction times given is generally suitable for these alkylates. With some 65 lips and Lovell (cf. J. Am. Chem. Soc. 58, 1944 (1936)). Where these isomerization processes of the hexanes, nonanes or decanes the range are applied to the gasoline-boiling normal paraf of reaction time is usually greater than the range given above, particularly where alkyla fins, there will be concurrent isomerization, cracking of the normal parañìns to low boiling tion catalysts less effective for the particular al kylate are used. The time required for reform 70 normal paran-ins, and reforming of the isomers ing also varies with the particular alkylate isom produced. The isomerization of normal paraiîlns ers being treated. For example, the heptanes is usually extremely slow under the comparative formed by the alkylation of isopentane with ly mild conditions used for reforming the ethylene are considerably slower in reforming 'to branched-chain paraflins. The boiling charac a uniformly boiling hydrocarbon mixture, than 75 terìstics of the product from such a` combined 2,403,929 , 6 5 Hydrocarbon soluble catalysts‘suc‘h as alumi processV isv not controllable-within ythe meaning num bromide, possess the advantage that molec ular contact is obtained between catalyst and hy withV which this term is used in‘my invention. The 'concurrent -isomerization and reforming' of gasoline-boiling, normal parafûns is not included within my invention. However, fractionation of drocarbon, hence a minimum of agitation is re such a hydrocarbon mixture to separate out a quired. The catalyst may be'subsequently re moved from thehydrocarbons by chilling, which narrow-boiling, branched-chain paraffin would will cause the catalyst to separate out as a solid, yield a distillate fraction suitable for treatment by my process to form a~hydrocarbon mixture of "desired distillation characteristics within the gasoline range. `Therefore, the reforming of. a narrow-boiling,` branched-chain isoparaffin ob or by distillation of the hydrocarbonsfrom the catalyst, preferably at reduced pressures.` 10 _and this not only serves to produce contactbe 35 Because the reaction involved in my reforming process is of suiiîcient intensity to produce hy drocarbons boiling over the entire gasoline range, therealso are produced smaller amounts of satu tainedin this> way, as well as from any other rated hydrocarbons boiling over and‘below the source, is to be considered as included within the scope of my invention. ~ , 15 gasoline range. In this connection, I have found that these less valuable saturated portions> vof The catalysts used in my process are both hy the reformed product distilling outside the gaso drocarbon soluble and hydrocarbon insoluble cata line range, e. g., below 25° C. and above 168°. C., lysts. Aluminum bromide is a typicalv hydrocar can be utilized for the production of additional bon soluble catalyst. The. hydrocarbon immisci ble catalysts are further capable of division. into 20 gasoline-boiling hydrocarbons by reacting these products together in the presence of essentially three groups based upon their physical properties anhydrous hydrogen fluoride, or other alkylating under the reaction Aconditions as follows: solid, catalyst. It should be noted that this reaction immiscible catalysts, typiñed by-aluminum chlo is not alkylation since both reactants are satu ride; liquid, immiscible catalysts, typìñedby sul . furic acid and hydroiiuoric acid; yand gaseous 25 rated hydrocarbons. Another feature of my invention is based >upon catalysts, typiñed by gaseous hydrogen iiuOride. my discovery that the distillation characteristics Because of the different physicalcharacteristics of the ñnal product may be influencedby. the ofv the various catalystsused, certain- „differences addition of minor amounts of either light isopar exist in the operating procedures followed in the carrying out-of my invention.V The ¿essentialfea 30 aûins such as isobutane or isopentane, or bythe addition of hydrocarbons boilingV above the gaso tures ofrthelinvention arethe same, regardless line range. The amount of this added hydrocar of the particular type of catalyst selected. bon `should be preferably less th-an an equimolar , _The gaseous catalysts may simply be bubbled quantity, and is of the general order` of from V5 to >up through « the hydrocarbon inoI packed tower, about, 40 mol percent of .the alkylate charge stock. Since these light and heavy hydrocarbons are end products of the reforming reaction, their presence in the reaction mixture has the effect, sary agitation. b flîhé catalyst, is _very easilyre also, of slowing down the reforming reaction. `_circulateol for recontacting withhthe same batch of hydrocarbons,V or ,» with a fresh hydrocarbon 40 Obviously, if too great a quantity of` these high and low boiling materials are present in the mix fory treatment.¿ HContinuous operation _is very ture, the desired catalytic rearrangement will be easily performed. `Ön a yolumetric basis, the largely suppressed. As a general practice neither -quantity of catalyst used is` fairly substantial tween hydrocarbon and catalyst, but WilLUin‘a properly designed reactor, produce _all'th'e fneces of these added hydrocarbons should be present relative _tothe Aquantity of hydrocarbon being reformed, thus requiring, in general,~ more costly in an amount much in excess of an equimolar quantity of the branched-chain hydrocarbon be ing reformed. As mentioned previously, the catalysts differ appreciably in their activity. `equipment than with the other typev catalysts.> Solid, iinmiscible catalysts, such as aluminum f >v"'c'zhlo‘rida;possessthe advantage VthatV bulk separa tion ofthe liquid gasoline produced fróm-'theÍs‘olid catalyst. is Very`simple. Considerable >agitation to” hydrocarbons added or recirculated should be less is required with catalysts'Y of this type «_to‘obtain than about an equimolar quantity (based upon elücient "contacting Moreover, the ‘ >all'irninum the hydrocarbons being reformed), and prefer chloride reacts with someof'the hydrocarbons „to >forni" al sludge, Viizhose regeneration' involves considerable additional processing. ' ` Immiscible liquid catalysts such‘as sulfuric‘acid and hydr'o'iluoric acid also possess the’advant'age that bulk separation of product from the catalyst involves a mere settling operation or its equiv -alent. In addition, hydrogen fluoride oifers the l further advantage that, since itis quite stable and has a normal boiling point'of> `19.4" C., it can be distilledV at ordinary temperatures and pres Isuresyvithout decomposition. Therefore, the hy drogen fluoride` catalyst can be easily and cheaply puriiied as often as necessary by a simple distilla tion procedure whereby it may bevreused indeli While the amount of either high- or low-,boiling ably should not exceed about ñfty mol percent, with some of the more active catalysts, or Where ' the extent of reforming desired is small, some what larger amounts of added hydrocarbons may be present. In the case of aluminum chloride, for example, amounts up to 200 mol percent of isobutane may be added, and in some cases'such a large addition might be desirable to enable bet ter control of the extent of the reforming reac tion. Without attempting to theorize as to the me chanics of the reaction by which a hexane, hep ~ tane or an octane, for example, reacts to form isobutane, isopentane, hexanes, etc., up to 10„to 12 carbon atom saturated hydrocarbons, I have found that the presence of a low-boiling isopar nitelyin my process. Hydrogen iluoride presents affin, such as isobutane or isopentane, or a high other‘advantages over sulfuric acid because of »its ‘lack’ of oxidizing effect-upon hydrocarbons per- „I-Ó boiling hydrocarbon, such as a decane, tends to mitting use at high temperatureswithoutdanger suppress the reaction towards the formation of these lower and higher boiling products. The of oxidizing the reactants', and low density land viscosity permitting relativelyV small expense for agitaticn‘and admixture ofÍ the catalyst and hy' Èdrocarbon inimiscible layers-:4" f1 Y' ï» result is the formation of a higher percentage of intermediate boiling products, and a slowing downof there'a'ction.’ ' - ’ ' agoaeae 8 7 As stated previously, the high- and low-boiling cycling these fractions to the reforming reactor. alkylate charge stock, a simple andnovel com bined process is possible »by using the same al kylation catalyst for the reforming step as was used` for the alkylation. In such a process, it is unnecessaryy to remove the alkylation catalyst from the alkylate product-containing, reaction mixture. Since it is usual to conduct alkylation Normally, less than 40 mol percent of the nar reactions with the use of a large excess of iso fractions may be combined andwill react to gether in the presence of an alkylation catalyst under alkylating conditions of temperature and pressure to form additional gasoline-boiling ma terial. This may advantageously be done by re row-boiling feed is reformed to material boiling parafûn, this isoparafiìn should either be re outside of the gasoline range, even in the absence 1,0 moved,V or, where its presence to influence the of added high- or low-boiling material. Since boiling range of the product is desirable, it may the rate of recombination of this recirculated be necessary to only remove a part of it. In any material is generally at least as rapid as the rate event excess isoparaiîin must be removed to an of production of these high- and low-boiling extent which will allow the reforming reaction materials from the narrow-boiling. feed, the total 15 to proceed. The excess isoparai‘lin should be molar ratio of the high-.- and low-boiling hydro reduced to less than 200 mol percent of the alkyl carbons to the narrow-boiling fraction in the ate product, and preferably to less than 100 mol reaction zone is less than 1 to l. >In some cases percent of the alkylate. The product-catalyst Where the reforming reaction yields` substantial mixture is reformed in the manner heretofore amounts of high- and low-boiling material, of 20 described by further agitation and contacting the order of 30 to about 5I) mol percent, and/or before separation. Therefore, another feature of the recombination of the recirculated highn and my invention is a combined alkylation and re low-boiling feed material is slow, Vrelative to its forming operation. In such a combined process rate of formation from the narrow-‘boiling feed, where excess isobutane, or other lightisoparaiiin the amount of the high- and low-boiling material 25 is 'formed in the reforming step as described pre recirculated Will be larger than the amount of viously, this light isoparanin may be used in the narrow-boiling fraction fed to the reaction zone. alkylation step tofmake additional narrow In such a case Ythe total molar ratio of >the recir boiling alkylate. My invention is not `to be con culated hydrocarbons will exceed l to l.. While strued, howeveizras limited to the use of the this slows down the reforming of the narrow boiling fraction, since gasoline-boiling material is being formedffroml the high- and low-boiling material, the overall result is the same; i. e., the 30 same >catalyst for the reforming as Was used for the' preparation of the initial alkylate charge stock. ‘ In FigureY l of the drawings there is shown formation Vof a material boiling over the entire, diagrammatically a complete set up for both or a desired- portion of the entire, gasoline range. 35 alkylating and reforming, »wherein hydrogen In some casesit is possible that the amount of fluoride is-the catalyst used in Iboth steps. In low-boiling material formed maybe much in ex this operation a suitable isoparafûn, such as iso cess of the amount of high-boiling material. If butane, is fed through line I, provided with con this is true, and if >the amount of this excess low trol Valve `2, to a mixing chamber ; 3, wherein boiling material (principally isobutane) is large 40 it is mixed with an olefin, such as propylene in ‘relative to the amount of narrow-boiling hydro troduced through line Il, provided with control carbonbeing processed, -it may be necessary to valve 5. This mixture is then fed to reactor 6, withdrawsome of this isobutane from` the proc in which a stream. of concentrated hydrofluoric ess. In other words. where mol quantities of acid -flows counter current to the hydrocarbon these recycled hydrocarbons are unequal, »the mol 45 charge. This Aacid is recycled from the bottom excess of the one present in the greater amount of alkylator 6, to the top thereof through line should not exceed about 100 to 200 mol percent l,y by means of pump 8. The alkylate, principally (depending upon the catalyst being used) of the heptanes‘ along with unreacted isobutane and narrow-boiling hydrocarbon *being` processed. In some entrained acid passes from the top of the the case of this addition of high- and low-boiling .50 alkylator through. line 9, to settling tank I0, hydrocarbons, the high-boiling and low-boiling Wherein‘the hydrocarbons and acid separate to materials probably react with the branched-chain two layers. vThe acid leaves the bottom of this hydrocarbon being processed-as well as with settling‘tank through Aline II and is‘returned to each other. This same reaction between the the alkylator along with the recycled acid pass reactant hydrocarbon being processed and recy 55 ing through line 1. The hydrocarbons flow from cled hydrocarbon or any added saturated i'sopar aiiin undoubtedly occurs where only a single ad ditionalV component is present. The exact me chanics .of the reaction occurring in a two or the settling tank through line I2, to fractionator I3, provided with suitable heating coil I4, where in the isobutane isl removed from the alkylate as` overhead through line I5. Suitable means 60 (not shown) are provided for returning some iso vention is not to be considered as bound to any butane to the'fractionatcr as reflux. The alkyl theoretical consideration. The manner in which ateproduct from the bottom of this fractionator these added hydrocarbons affect the reaction is flows _through line IG, provided with pump Il, immaterial. The resulty is that `the catalyt‘i‘c're , more component System is not clear, and my in arrangement favors the formation'of less hydro carbons boiling above and below the gasoline range. >Where onlylone type of hydrocarbon is added, the.`material to be reformed should con stitute at least 35 to 50 molv percent of the total mixture. Asa consequence ofthe. e?îectfof _these added hydrocarbons, a simple procedure for con to reformer I8. In this reformer, as in the al kylator, a stream of concentrated hydrofluorlc acid _flows counter current to the hydrocarbon charge.l lI‘he reformed hydrocarbons pass throughy line I9,-to settling tank’ 20„vvherein the mixture hydrocarbons and entrained acidseparate into 7,0 of two layers in the manner previously described. trolling and regulating the distillation character The acid being recycled passes from the .bottom istics of .the finall product is available.,- of> the` reformer through line 2|, provided with pumps-x22, tothe top thereof. The acid layer from the settling tank 20, is `»returned to the lbull: , _ Y Inasmuch as my process involves theuse vof an alkylation catalyst for the> _treatment of an 2,403,929'> oftheV recycled acid in line 2|, through line 23. The hydrocarbons from the settling tank 20, flow by -line 24, to fractionator 25, provided with a suitable heating coil 26, wherein isobutane along Gasoline Original fraction alkylate (25°-160° C ) of reformed product with small amounts of isopentane are removed byi fractional distillation overhead through line Octane rating, A. S. T. M. method: 21. Means (not shown) are provided for re » - Y No TEL ____________________________ _. fluxing part of the fractionator overhead. The 69. 9 ` . 74.8 83 ' 88.9 '85 - 92.3 overhead from the fractionators in lines I5 and 21, are combined in line 28, and returned to the isobutane feed line I. lIfhis line 28 is provided with a suitable pump 29. The bottoms from the G9. 2 73. 4 , 79.8 84.4 fractionator pass through lineal), provided with > 185 pump 3|, to scrubber 32, wherein the last traces of hydrogen fluoride are removed by washing with an aqueous alkaline solution circulating L’ ., F ............. _.f'. ____________ __ Reid vapor pressure at 100° F ___________ ,_ through line 33, provided with pump v34. The scrubbed product ñows through line 35, to - 88.6 91.8 172 ,_ 105 137 190 192m ` v‘182 _ 201 199 Y 222 >208 "310 4. 5 _ 6.9 It will be noted that the gasoline-boiling.frac-U stabilizer 36, where the gasoline fraction is re moved by distillation through line 31, as an over 20 tion of the reformed product meets thedistilla. tion Aand vapor pressure requirements for aviation head product. The stabilizer is provided with a gasoline and has an unleaded octane number al suitable heating coil 38, and means (not shown) most 5 points higher than the original4 alkylate. are provided for reñuxing part of the overhead. It possesses the same high lead susceptibility as The bottoms from the stabilizer are fed back - ` . through line 39, either to the mixing chamber 25 the original alkylate, i. e., about 2.1. . The gaseous by-product distilling-below` 25° C. via line 49, or to the reformer via line 4 I, where was composed entirely of isobutane, and was re in these bottoms are reacted in' the presence of acted with the fraction distilling above 160° C. concentrated hydroñuoric acid and the lighter to producean additional quantity of aviation boil isoparaiiîns to give additional quantities of gaso line-boiling range material. Valves 42 and 43 30 ingrange gasoline. To illustrate the procedure for doing this the fraction distilling above 150°_C., are provided with lines 40 and 4l, respectively, which amounted to 439 parts by weight, „was whereby the distribution of the return of the mixed thoroughly with 300 parts by weight of stabilized bottoms may be controlled. Line y44 is provided so that a suitable portion of the over head from fractionator 25 may be recycled di isobutane and 240 parts by weight of anhydrous aluminumy chloride for 7 hoursatroomtempera~ rectly to> the reformer, although these light iso ture in a steel autoclave. ' During this time a gradual pressure drop from about29 to about 21 paraffins may also 'be obtained in the reformer pounds per square inch (gage) took placer. `In by regulating the amount of excess light iso this reaction there wasa pressure drop sincethe parafûn taken overhead from the fractionator I3. Valves 45 and 46 are provided for controlling 40 the reaction products normally havea lesser vapor pressure than the original high- and low-boiling the distribution of the overhead from fraction fractions. As in the previous ease, this change ator 25. in the pressure was used as a measure ofthe ex-V The following speciñc examples of >operation tent of reaction. Agitationwas then.- discon are given to further illustrate the principles of my invention and the advantages obtained by 45 tinued, the hydrocarbon phase separatedffrom the catalyst, and the gasoline fraction distilling my process. These examples are illustrative in the range 25° to 160° C. recovered as inthe only, and are not to be `construed as limiting previous case. .This fractionamounted Vto., over the scope of my invention to the details set forth 60 percent by weight of the total product and therein. ~ 50 had approximately the same composition as the Example I corresponding fraction obtained by catalytic` re A_n alkylate charge stock composed principally forming of the original alkylate. -. l - . . , _ , parts by Weight produced by the reaction of iso By repeatedly reacting the light ends with the heavy ends and removing the gasoline range oughly with 1350 parts by'weight of anhydrous gasoline of high octane rating which meetsthe of branched-chain heptanes in an amount of 4290 pentane with ethylene in the presence of an 55 material by fractionation, therefore; substantially all of the original alkylate can- be converted to hydrous aluminum chloride, was mixed thor.. distillation and vapor pressure requirementsv for aviation gasoline. The continuous recycling pro gradual pressure rise from about l to about 8 60 cedure already described is, of course, preferable for carrying out this process on a commercial pounds per square inch (gage) took place. This aluminum chloride for 7 hours at room tempera ture in a steel autoclave. During this time a scale. pressure rise was caused by the formation of pro portionately larger amounts of light isoparafñns having normally a higher vapor pressure than the 65 alkylate charge stock, and was used as a measure of the extent ofreaction. - Agitation was then discontinued and the hydrocarbon phase sepa l . Example II _ 1380 parts by weight of alkylate' (principally branched-chain >octanes), having an octane nurn ber by the A. S. T. M_ method of 93, produced by reaction of i'sobutane with normal butene in the presence of concentrated hydroiluoric acid, were rated from the catalyst, washed with water, and dried over .anhydrous calcium chloride. The dried 70 mixed thoroughly with 1328 parts by weight of hydrocarbons were then fractionated to recover hydrofluoric acid for 15 hours at room tempera the gasoline distilling in the range 25° to 160° C. ture in a steel autoclave to obtain substantially f The properties of this fraction and the original complete reforming of this alkylate. During this alkylate are given in the following table for com time a gradual pressure rise from about 23- to parison: . *Y f . 7.5 about 27 pounds per square inch (gage) « took 2,403,929 11 12 place, which was used as a measure of the extent of reaction. Affitation was then discontinued and tent of reforming in this experiment fell midway between that obtained in the two previous exam ples as shown by the distillation curve, D, of the the two liquid phases, i. e., the hydrocarbon phase and the hydroiiuoric acid phase, allowed to sepa liquid product boiling above isopentane in Fig rate. Thehydroñuoric acid phase was withdrawn ure 2. as the bottom layer and the hydrocarbon phase The following examples were performed to show washed with water, dried over anhydrous calcium the effect of an added hydrocarbon, boiling out side the gasoline range on the reforming process. chloride, and fractionated to recover the gasoline distilling in the range 25° to 168° C. Example VI The gaseous by-prcduct distilling below 25° C. The experiment described in Example IV was was composed entirely of isobutane, and was re repeated except that 46.5 mol percent of isobutane acted with the fraction distilling above „168° C. was added to the alkylate charge before contact to produce an additional quantity of gasoline ing it with the acid for 14 hours. The extent of boiling range material. To illustrate the proce dure for doing this the fraction distilling above 15 reforming in this experiment was appreciably less than that obtained in* the absence of iso 168° C. which amounted to 317 parts by weight butane as shown by the distillation curve, E, of was mixed thoroughly with 216 parts by weight the liquid product in Figure 2. ' of isobutane and 447 parts by weight of concen trated hydrofluoric acid for 9 hours at room tem Enample VII perature in a steel autoclave. During this time 20 The experiment in Example III was repeated a gradual pressure drop from about 40 to about except that 104Y mol percent of isobutane was 35 pounds per square inch (gage) took place added to the alkylate charge before contacting which, as in the previous cases, was used as a it with the acid for 24 hours. Distillation curve measure of the extent of reaction. Agitation was then discontinued, the two liquid phases sepa 25 F in Figure 2 shows the extent of the reforming obtained in this experiment. rated, and the hydrocarbon phase fractionated As mentioned above, the distillation curves for as before to recover the gasoline fraction dis the products of Examples III to VII boiling above tilling in the range 25° to 168° C. isopentane Yhave been plotted in Figure 2. This The properties of the composite gasoline pre pared in this manner are given in the following 30 graph, wherein volume percent of gasoline-boil ing material distilled is plotted againstV distilla table: tion temperature, effectively illustrates the utility of my invention. For comparison purposes, the distillation curve of the original heptane fraction Plus 3 cc. No TEL TEL/gallon k35 Octane rating: A. S. T. M. method_._ 84. 2 100. 0 Research ’39 method. _ 83. 3 97.3 A. B. T. M. distillation: 50% 70% 90% Temperature, °F .... ._ 126 223 247 272 E. P. 320 propylene is shown as curve A. This curve shows that this heptane alkylate has a narrow-boiling range between 80 and 100° C. By a comparison of curve A with curves B, C, l Vol. per cent distilled__ 10% obtained by the` alkylation of isobutane with 40 and D, the effect of the reforming reaction on the'boiling range of the alkylate fraction may be readily seen. Approximately 85 percent of the product boiling above isopentane distilled rather uniformly over the entire gasoline range. The lower-boiling material, not shown in the curves, constituted about 30 percent of the orig inal heptane fraction, and was about equally divided between isobutane’and isopentane. The isopentane fraction is, of course, suitable for use Reid vapor pressure at 100° F _____________________________ __ 8 pounds per square inch It Will be noted that this product has an A. S. T. M. octane number of 100 with only 3 cc. of tetraethyl lead per gallon. Substantially com plete reforming was obtained in this case as shown by the high vapor pressure and the appreciable quantity of low- and high-boiling hydrocarbons. Example III 50 in gasoline, so about a total of 70 percent of the original heptane fraction was recovered directly 19.7 parts by? weight of alkylate (principally as a gasoline fraction ofW uniform distillation branched-chain heptanes) , produced by reaction characteristics over the entire gasoline boiling of isobutane with propylene in the presence of range. concentrated hydroiiuoric acid, were mixed thor Curves B, C, and D show the effect of time upon oughly with 26 parts by weight of concentrated 55 the reaction. The extent of reforming is sub hydrofluoric acid for 24 hours at room tempera stantially the same over the entire time range of ture. The liquid product from this reaction was 4 to 24 hours. Curve B shows that somewhat recovered as in Example II. Substantially com more reforming was obtained at 24 hours than at plete reforming was obtained as shown by the distillation curve, B, of the portion of the product 60 14 hours shown in curve C. Where the reform ing reaction was allowed to proceed for only 4 boiling above isopentane in Figure 2. hours, substantially the same degree of reforming Example IV was obtained by slightly increasing the amount The experiment described in Example III was of catalyst used, as shown by curve D lying in repeated except that the time of contact between 65 termediate curves B andk C. the hydrofluoric acid and the _alkylate was 14 A comparison of curves C and E shows the effect hours. The distillation curve, C, of the liquid of an added hydrocarbon boiling outside the gaso-Y product boiling above isopentane is given in Fig ure 2. Eâllample V line range on the process. The effect of the added hydrocarbon, isobutane, was to increase 70 the proportion of intermediate boiling material'. The experiment described in Example III was repeated except that a larger weight ratio of catalyst to alkylate was employed, i. e., 1.56 in stead of 1.32, andthe time of contact between catalyst and alkylate was only 4 hours. The ex 75 In the presence of isobutane (46.5 mol precent) over 65 percent of the material boiling above isopentane boiled within the range from 60 to 120° C. In the absence of isobutane only about 45 percent of the material boiling above isopentane 2,403,929 14 13 to be understood narrow-boiling, branched-chain hydrocarbon fractions in general may be used. For instance, such a product formed by polymer izing oleñns and then hydrogenating the poly boiled in this same range. The amount of mate rial boiling above the gasoline range was less than l0 percent, as compared with about 15 percent in the case of reforming in the absence of iso butane. The amount of total low-boiling mate rial, not shown on the graph, was also consider mers could serve as a stock to be reformed. Many modifications of my invention will be apparent to those skilled in the art, and only ably less, making the total gasoline-‘boiling mate rial, including isopentane, about 85 percent. such limitations should be imposed as are indi cated in the appended claims. Curve F shows that where the amount of iso I claim: butane added, in the case of the hydrofluoric acid 10 1. The process which comprises contacting a catalyst, exceeded an equimolar quantity the re mixture of an isoparaûin and an olefin in which forming reaction was almost completely sup the mol ratio of the isoparaifln to the oleñn is pressed. The reaction was allowed to proceed for greater than two to one with an alkylation cata 24 hours, and the curve shows that in the pres ence of such a large amount of isobutane, an ex cessively long time would be required to obtain 15 lyst consisting essentially of hydrofluoric acid under alkylating conditions of temperature and pressure for said catalyst to form a relatively narrow-boiling alkylate, separating at least a suf The curves show that in the absence of added ficient amount of the isoparai’n‘n from the hydro isobutane, the contact time may be varied from about one hour to about 24 hours without appre 20 carbon product mixture to reduce the isoparaf?n alkylate mol ratio to less than one to one, con ciably altering the results. 'I'his is evidence that tacting the alkylate product containing less than with an active catalyst equilibrium is established one mol of isoparaflin per mol of alkylate with in the system in a comparatively short time. In an alkylation catalyst consisting essentially of case it is desired that the major fraction of the hydroñuoric acid under alkylating conditions of reformed product boil over but a limited portion temperature and pressure to reform said alkylate of the gasoline range, contact times of less than to higher and lower boiling saturated hydrocar about one hour may be used, the concentration bons, allowing the hydrocarbons and catalyst to of the catalyst may be lowered, or a low- or high remain in contact until the desired amount of boiling hydrocarbon added. appreciable reforming. It is important to note that the reformed prod uct obtained by my process is not a low octane 30 product as might be expected, but rather it hasY an octane rating that compares favorably with that of the original alkylate and is frequently higher than that of the original alkylate. When dealing with a narrow-boiling, branched-chain the original narrow-boiling fraction has been re formed to give a mixture of hydrocarbons whose boiling range has a desired distribution over the gasoline boiling range, separating the hydrocar bons from the hydrofluoric -acid catalyst, frac tionating the hydrocarbons to remove saturated hydrocarbons boiling below and saturated hydro carbons boiling above the desired range, returning fraction of relatively low octane number, such as the hydrocarbons so separated in admixture for the ordinary heptane alkylates, the octane num further contacting with the alkylation catalyst, ber is raised in addition to obtaining a desired spread in the boiling range. Some of the al 40 and recovering the desired hydrocarbon fraction kylates, such as the isobutane-butylene alkylate of controlled-boiling characteristics. 2. The process which comprises contacting a of Example II, which have a very high octane mixture of an isoparaflin and an olefin in which number, will give a somewhat lower octane rating the mol ratio of isoparailin to the olefin is greater for the reformed product. The reformed prod uct, however, might easily have a higher octane 45 than 2 to 1 with an alkylating catalyst consisting rating than the motor fuel obtained by blending the high octane alkylate with the blending agents available and capable of giving the alkylate the proper boiling characteristics. Also a partial re forming of a high octane alkylate so that it may I be blended with available blending agents to give a complete motor fuel may frequently be desirable, and such a partial reforming could be accom plished at a lesser sacriñce of octane number. The improvement in the boiling characteristics of the alkylate will frequently be desirable and necessary for the effective utilization of a particular al kylate, and for the production of a high octane complete fuel. The process is therefore of value for the treatment of high octane alkylates as well as the lower octane alkylates, even though with the former there is some sacriñce in the octane number of the alkylate itself. The octane rating of my reformed products may be easily brought up to aviation requirements by the addition of small and permissible amounts of tetraethyl lead. It is also important to note that my process is capable of producing a complete gasoline, and that in so doing, a larger percentage of the al kylate, and hence a larger percentage of gaseous hydrocarbons going into alkylate, will be repre sented in the finished product. The invention has been described with particu lar reference to alkylate gasolines; however, it is essentially of hydrofluoric acid under alkylating conditions of temperature and pressure for said catalyst to form a relatively narrow-boiling al kylate, separating a suiiicient amount of isopar ai-lin from the hydrocarbon product mixture to reduce the isoparaffin-alkylate mol ratio to less than 1 to 2 contacting the alkylate product con taining less than one-half mol of isoparaflin per mol of alkylate product with an alkylation cata lyst consisting essentially of hydrofluoric acid under alkylating conditions of temperature and pressure to reform said alkylate to higher and lower boiling saturated hydrocarbons, allowing the hydrocarbons and catalyst to remain in con tact until the desired amount of the original narrow-boiling fraction has been reformed to give a mixture of hydrocarbons whose boiling range has a desired distribution over the gasoline boiling range, separating the hydrocarbons from the hydroñuoric acid catalyst, fractionating the hydrocarbons to remove saturated hydrocarbons boiling below and saturated hydrocarbons boiling above the desired range, returning the hydrocar bons so separated in admixture for further con tacting with the alkylation catalyst, and recover ing the desired hydrocarbon fraction of controlled boiling characteristics. CARL S. KUHN, JR.